Liquid crystal elements and method of producing same

ABSTRACT

A display element for use in computer terminals, television displays and other information display devices capable of large capacity, full color display employing active elements, wherein an optical layer comprises liquid crystal and polymer dispersed in one another. The polymer comprises polymer grains directionally aligned in the optical layer by directional alignment of the liquid crystal, which is aligned by treatment provided relative to at least one of the substrates forming the display element. The polymer grains are developed from the polymerization of at least one polymer precursor containing at least one polymerizable portion and at least two aromatic rings with a coupling group provided between the aromatic rings. The polymer precursor contains, as at least one component, a polymer compound without an alkyl group spacer between the polymerizable portion and the aromatic rings.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to a polymer dispersed liquid crystaldisplay element wherein the liquid crystal and polymer are dispersedinto one another, and, more particularly, to a display elementapplicable to user interfaces employed for computer displays andtelevision and the method of producing such display elements.

2. Background of the Invention

With the introduction of computers to society in recent years, thedevelopment of user interfaces has accelerated. The development ofdisplays is particularly fast paced, but currently the market dependsprimarily on twisted nematic liquid crystal display devices, whichemploy two polarizing plates providing a display that is dark. To solvethese problems, polymer dispersed liquid crystal display devices havebeen recently developed. Since these systems do not require polarizingplates, the incident light to the display can be effectively employed.In particular, in operational modes that utilize dichroic dye, theappearance of the element is remarkable when employed as a reflectingtype. For example, Fergason utilizes capsulated liquid crystalcontaining dichroic dye which is dispersed with polymers, as disclosedin Japanese Laid-Open Patent Publication 3-52843, hereinafter referredto as normal polymer PDLC mode. Also, Doane, et al., has proposed aproduction method whereby liquid crystal containing dichroic dye andpolymer precursors are combined and the liquid crystal and polymer arephase separated into a sponge state as performed through polymerization,as disclosed in Japanese Patent Publication 61-502128, hereinafterreferred to as normal polymer PDLC mode. Furthermore, employing polymerprecursors which take on a liquid crystal state, Hikmet, et al., ofPhilips Corporation, provided a display element with a structure thatwas formed with polymer in an aligned state, which is achieved byirradiation with ultraviolet light while in a mixed condition withliquid crystal, and in which the liquid crystal was contained in a gelnetwork, as disclosed in Mol. Cryst. Liq. Cryst., Vol. 213, pp. 117-131,1992, hereinafter referred to as network type aligned PDLC mode. Unlikepreviously described modes, the display element of this mode scatterswhite when an electric field is applied. We have, however, independentlydeveloped technology that forms polymer into grains or macromoleculeswhile they are in an aligned state as disclosed, for example, in EPOPublication 488116, hereinafter referred to as grain-aligned PDLC mode.However, sufficiently desired brightness and contrast level cannot beachieved in these modes. Moreover, the driving voltage is not ofsufficiently desired low value.

The purpose of the invention is to offer a display element andassociated manufacturing method wherein the liquid crystal and polymerare aligned and dispersed in one another providing high brightness andgood contrast with low driving voltage.

SUMMARY OF THE INVENTION

According to this invention, a liquid crystal and polymer are alignedand dispersed in one another wherein the polymer or polymers employedare derived from one or more polymer precursors having a polymerizableportion. More particularly, such polymer precursors include at least onecomponent as a polymer precursor having a polymerizable portion and aside chain portion. Alternatively, they may include polymer precursorshaving two or more polymerizable portions comprising at least onecomponent. The polymer precursors may comprise either ester derivativeswith methacrylic acid or acrylic acid, or they are amide derivativeswith methacrylic acid or acrylic acid. The polymer precursors contain atleast one component comprising a compound having an epoxy group. Thepolymer precursors may also contain at least one component comprising acompound having at least two aromatic rings, or at least one of thearomatic rings may by hydrogenated, and an ester group between thearomatic rings. The polymer precursors may also contain at least onecomponent comprising a compound having at least two aromatic rings or atleast one of the aromatic rings may by hydrogenated, and a urethanegroup or an amide between the aromatic rings. The polymer precursors mayalso contain at least one component comprising a compound having atleast two aromatic rings, or at least one of the aromatic rings may byhydrogenated, and at least one acetylene group between the aromaticrings. Also, a cyano group, a halogen group or an aromatic ring may bebonded either directly or indirectly to the aromatic rings contained inthe polymer precursors. Also, an alkyl group or alkoxy group may bebonded to the polymer precursors.

The above polymer precursors may also contain an optically activepolymer compound. The polymer may also contain at least one componentcomprising a polymer compound containing fluorine. The liquid crystalmay also include dichroic dye. The liquid crystal may also include achiral component. The liquid crystal is a nematic liquid crystal.

The polymers are formed by stimulating a mixture of the polymerprecursors and liquid crystal by means of at least one of the groupcomprising stimuli heat, light and an electron beam. The polymers areformed by first polymerizing the polymer precursors and rendering themcompatible with the liquid crystal by gradually heating, after whichthey are slowly cooled. Alternatively, the polymers are formed by firstpolymerizing the polymer precursors and rendering them compatible withthe liquid crystal by employing a solvent, are then spread onto asubstrate, after which the solvent is slowly removed in a manner toallow the polymers to phase separate while aligned with the liquidcrystal. The direction of alignment of the liquid crystal/polymer layeris inclined with respect to the surface of the substrate. Also, thedirection of alignment of the liquid crystal and the polymer layer iscontrolled by an alignment treatment of the substrate surfaces betweenwhich the liquid crystal/polymer layer is employed. Relative to aparticular substrate for alignment of the liquid crystal/polymer layer,the alignment treatment of at least the substrate on the light incidentside of the display element is applied in a direction perpendicular tothe plane including the plimary direction of light incidence and thenormal line of the light incident substrate. Alternatively, thealignment treatment of the light incident substrate is applied in theplane including the primary direction of light incidence and the normalline of the substrate. A light reflective layer or a light diffusinglayer is disposed on the back face of the liquid crystal/polymer layer.An optical phase shift plate, e.g., 1/4-wavelength plate, is disposedbetween the liquid crystal/polymer layer and the reflective layer orlight-diffusing layer. A color filter is formed on at least one of thesubstrates between which the liquid crystal/polymer layer is employed.Active elements, e.g., two-terminal elements or three-terminal elements,are formed on at least one of the substrates between which the liquidcrystal/polymer layer is employed.

Two display elements of this invention may be mated together such thatthe directions of alignment of the liquid crystal/polymer layers areperpendicular to one another. The method of producing the displayelement of this invention comprises forming the liquid crystal/polymerlayer by stimulating a mixture of the polymer precursors and liquidcrystal by at least one means from the group comprising of the stimuliheat, light and an electron beam, polymerizing the polymer precursorsand rendering them compatible with the liquid crystal by graduallyheating, after which they are slowly cooled, or alternativelypolymerizing the polymer precursors and rendering them compatible withthe liquid crystal by employing a solvent and spreading a layer thereofon a substrate, after which the solvent is removed sufficiently slow toallow the polymers to phase separate while aligned with the liquidcrystal.

Other objects and attainments together with a fuller understanding ofthe invention will become apparent and appreciated by referring to thefollowing description and claims taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic cross sectional view of a horizontally aligneddisplay element according to a first embodiment of this invention.

FIG. 2 is a diagrammatic cross sectional view of a vertically aligneddisplay element according to the first embodiment of this invention.

FIG. 3 is a diagrammatic cross sectional view of an incline aligneddisplay element according to the first embodiment of this invention.

FIG. 4 is a partial cross sectional elevation of a display elementemploying active elements according to a thirteenth embodiment of thisinvention.

FIG. 5 is a partial cross sectional elevation of a display elementemploying a color filter according to a fourteenth embodiment of thisinvention.

FIG. 6 is a perspective view of a display element according to aneighteenth embodiment of this invention.

FIG. 7 is a graphic illustration of the electro-optical characteristicof a display element according to the eighteenth embodiment of thisinvention.

FIG. 8A a perspective view of a horizontally aligned display elementaccording to a nineteenth embodiment of this invention in the absence ofan applied field.

FIG. 8B a perspective view of a horizontally aligned display elementaccording to a nineteenth embodiment of this invention under theconditions of an applied field.

FIG. 9A a perspective view of a vertically aligned display elementaccording to the nineteenth embodiment of this invention in the absenceof an applied field.

FIG. 9B a perspective view of a vertically aligned display elementaccording to the nineteenth embodiment of this invention under theconditions of an applied field.

FIG. 10A a perspective view of two mated display elements according to atwentieth embodiment of this invention in the absence of an appliedfield.

FIG. 10B a perspective view of two mated display elements according to atwentieth embodiment of this invention under the conditions of anapplied field.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention is explained in more detail with reference to severalembodiments relative to the drawings.

First Embodiment

In this embodiment, a methacrylate ester or acrylate ester derivative isemployed as the polymer precursor, which have two or more aromatic ringsin the side chain, at least one of which may be hydrogenated. A polymerprecursor with an ester group is employed between the aromatic rings.FIG. 1 shows a cross section of a horizontally aligned display elementof this invention. FIG. 2 shows a cross section of a vertically aligneddisplay element of this invention. Thus, the invention can be applied toboth horizontally aligned and vertically aligned types of displayelements. In this embodiment, a horizontally aligned type is mainlyexplained for the sake of convenience. In all of the embodiments below,vertical alignment of the element substrates may be performed and liquidcrystal with a negative dielectric anisotropy may be employed.

The production method of the element is explained. First, electrodes 2and electrodes 5 are formed on the surfaces of substrate 1 and substrate6, which have flat surfaces. Either of these electrodes may bereflective. The substrate surfaces undergo alignment treatment. The twosubstrates are fixed such that the gap between them is 5 μm. This neednot be 5 μm and may be decided based on the application. For example,since the light path length is cut in half if the device is used as atransmission type, sufficient contrast cannot be obtained unless the gapis doubled to 10 μm from 5 μm.

A nearly transparent element is produced by injecting 4-benzoyloxyphenyl methacrylate, ##STR1## as the precursor for polymer 3 and liquidcrystal 4 (comprising a mixture of product No. PN002, available fromRodic Company, 1% of product No. S-1011, available from Merck CO., as achiral component, and 1.5% of product No. S-428, available from MitsuiToatsu Senryo K K, as a dichroic dye) in a 1:9 ratio and orienting thismixture, after which phase separation of the liquid crystal and polymerwas performed by irradiation with ultraviolet light.

The electro-optical characteristics of the display element were measuredin conjunction with a reflective plate, which was disposed behind thedisplay element and an AC electric field with a frequency of 10 KHz wasapplied between the two electrodes. Then the reflectivity of light fromthe display element was measured while varying the voltage. At 3.3V, thedisplay condition started to invert (5% reflectivity), and at 4.8V itbecame saturated (190% reflectivity). Compared to the prior art, thedrive voltage dropped, though only slightly, and the degree ofscattering of was improved. Reflectivity was measured by comparison withthe reflectivity of white paper, which was set at 100%. By disposing thedisplay element so that the direction of alignment of the polymer grainsor macromolecules positioned at either the front surface of the displayelement or the rear surface of the display element are perpendicular toa plane that includes the direction of incident light and a line normalof the display element surface, reflectivity is improved. In contrast,when photo-cured biphenyl derivative 4-biphenyl methacrylate is employedas the polymer precursor to produce a display element by the same methodas this invention, which the inventors have previously employed, thedisplay condition started to invert at 3.5V (5% reflectivity) andbecomes saturated (180% reflectivity) at 5.0V. In the case here, 100%reflectivity is when a sheet of white paper was disposed in lieu of thedisplay element. It is clear that the method of this embodiment improvesscattering at low voltage operation.

The characteristics of the display element were also measured using atransmission type optical system. In this case, the display element wasproduced with transparent electrodes formed on the display elementsubstrate without incorporation of dichroic dye. The brightness of thelight transmitted by the display element was measured compared to thebrightness of the incident light, which was set at 100%. An aperture wasdisposed directly in front of the light detector to eliminate scatteredlight from the display element. The diameter of the aperture was set sothat the viewing angle of the element was 3°. The electric field appliedon the display element was applied under the same conditions as above.The display condition began to invert at 3.5V (85% transmissivity), andthe display became saturated at 5.0V (5% transmissivity). Theapplication here may be either the transmissive type or the reflectivetype.

In another example, a display element utilized an ester group includedbetween a biphenyl group and a phenyl group that includes three or morearomatic rings. For example, 4-(4'-biphenyl carboxyl) phenylmethacrylate is employed. ##STR2##

The display element was produced and voltage driven in the same manneras described above. The display condition began to invert at 4V (5%reflectivity), and the display became saturated at 5.5V (190%reflectivity). The same effect was demonstrated with a transmissive typedisplay.

In a further example, a display element utilized a naphthalene groupincluded in the polymer precursor, and the direction in which the estergroup is added is opposite. Other than the kind of polymer precursor,the display element was produced under the conditions as previouslydescribed. Here, 4-(2'-naphthoxy carbonyl) phenyl methacrylate wasemployed as an ultraviolet-cured polymer precursor. ##STR3## The displaycondition began to invert at 3V, (5% reflectivity), and the displaybecame saturated at 4V (80% reflectivity). The same effect wasdemonstrated with a transmissive type display.

The same effects are achieved with polymer precursors other than thosedescribed above if the polymer precursor has a basic skeleton formulaindicated by ##STR4## wherein P₁ and P₂ include aromatic rings, thegroup in the parentheses may be bonded in reverse, and

R is H or CH₃.

In the foregoing examples, the polymerizable portion employed in thepolymer may be acrylic, methacrylic, crotonic acid, fumaric acid, maleicacid, a vinyl group, an epoxy group or other polymer group. Of course, Rin the foregoing chemical formula may be an alkyl group or othersubstituent. Also, a polymer precursor with a polymerizable portion thatis hardened by means of heat or an electron beam may be employed.Regarding the aromatic rings, at least one of them can be hydrogenated.For example, ##STR5## may be employed. The aromatic rings are notlimited to phenyl groups, as biphenyl, terphenyl, naphthalene,anthracene and other polycyclic aromatic rings can be employed.Para-substitution was used as the substitution mode for the aromaticrings, but they will function as a display element withmeta-substitution or ortho-substitution. However, the degree ofscattering readily drops. Further, though there are no substituents inthe aromatic rings other than bonds with other aromatic rings, superiorcharacteristics can be manifested by inserting such substituents as acyano group, a halogen group, an alkyl group or an alkoxy group asdescribed below. Also, at least one of the structures of the urethanegroup, amide group or acetylene group, described later, can be employed.Fluorine may also be substituted for H in the compound.

Ultraviolet light is employed when an external field is applied at thetime of polymerization, utilizing a wavelength between 300 nm to 400 nmwith an intensity of 2 mW/cm². Any wavelength and intensity may beemployed, however, that will polymerize the polymer precursor.Particularly in the case wherein weak light is irradiated for a longperiod of time, it becomes more difficult for dichroic dye to becontained in the polymer when dichroic dye is employed, for the purposeof improving optical characteristics. When an initiator or sensitizer ismixed in the mixture, polymerization can be effectively promoted.Polymerization can also be performed by means of an electron beam. Forexample, sufficient polymerization can be achieved by employing anelectron beam accelerated at 250 KV by making the thickness of thesubstrate on the side on which the electron beam is incident to themixture sufficiently thin, e.g., 100 μm. It is also possible to mix in apolymerization initiator and achieve polymerization with heat.

Alignment treatment may be performed by any conventional means foralignment of the liquid crystal phase, such as, rubbing the baresubstrate surface, forming an alignment film and rubbing the surface ofthe alignment film, employing oblique deposition, employing an LB filmor employing a vertical alignment agent. Also, alignment treatmentapplied to only one substrate is effective. The direction of substratetreatment alignment may be in any direction, and the alignment directionof the front substrate and that of the rear substrate can be different.However, it is necessary to optimize the direction to match thedirection of incident light and the diffusion profile required for thedisplay element. Also, as described later, by inclining the direction ofalignment of the polymer grains with respect to the substrate surfaceand reducing the drive voltage, the direction of distinctive visibilitycan be optimized.

The liquid crystal employed should have an index of refractiveanisotropy, Δn, as large as possible. Also, the dielectric anisotropy ofthe liquid crystal may be positive. The preferred amount of liquidcrystal contained in the mixture is in the range between 50% to 97% withrespect to the polymer precursor. When the amount of liquid crystal isless than this amount, the mixture will not respond to an electricfield. When the amount of liquid crystal is more than this amount,contrast cannot be achieved. Also, by employing liquid crystal with highresistivity, the liquid crystal can be driven by means of activeelements.

The dichroic dye employed need not be that described here. Also, itscontent ratio can be optimized depending on the particular application.If dichroic dye is not mixed in the mixture, a mode is made possiblewherein the display element is transparent when the applied electricfield is OFF and is scattered white when the applied electric field isON.

In the examples here, a chiral component was mixed in the mixture, butwhich chiral component is employed is not critical and the amount mixedin the mixture can be determined based on the particular application.When a large amount is mixed in the mixture, the drive voltage must beincreased, but a memory characteristic is manifested. The displayelement will also function in the case where a chiral component is notemployed in the mixture.

Second Embodiment

In this embodiment, the polymer precursors are an ester methacrylate orester acrylate derivative having two or more aromatic rings as a sidechain and at least one of the aromatic rings may be hydrogenated. Apolymer precursor with a urethane group or an amide group is employedbetween these aromatic rings. The polymer precursor employed was4-methacryloyloxy phenyl-phenylcarbamate. ##STR6## The display elementwas produced in the same manner under the same conditions as employed inthe first embodiment.

The electro-optical characteristics of the display element were measuredby the method employed in connection with the first embodiment. Thedisplay began to invert at 3.5V (5% reflectivity), and the displaybecame saturated at 5V (180% reflectivity).

In another example, an amide group was employed as the polymerprecursor. Phenylcarbamoyl phenyl-4-methacrylate, ##STR7## was employedas the polymer precursor, and the display element was produced under thesame conditions as in the case of the first embodiment.

The electro-optical characteristics of the element were measuredaccording to the method of the first embodiment. The display began toinvert at 3.5V (5% reflectivity), and the display became saturated at 5V(180% reflectivity).

In addition to the polymer precursors described above in thisembodiment, the same effect can be achieved with any polymer precursorhaving the following basic skeleton formula: ##STR8## where, P₁ and P₂include aromatic rings, A is either OCONH or NHCO, which may be bondedin reverse, and

R is H or CH₃.

Here, the polymerizable portion may be acrylic, methacrylic, crotonicacid, fumaric acid, maleic acid, a vinyl group, an epoxy group or otherpolymer group. Of course, the R in the chemical formula may be an alkylgroup or other substituent. Also, a polymer precursor with apolymerizable portion that is hardened by means of heat or an electronbeam may be employed. Regarding the aromatic rings, at least one can behydrogenated. For example, ##STR9## may be employed. The aromatic ringsare not limited to phenyl groups, as biphenyl, terphenyl, naphthalene,anthracene and other polycyclic aromatic rings can be employed.Para-substitution was used as the substitution mode for the aromaticrings, but they will function as an element with meta-substitution orortho-substitution. However, the degree of scattering readily drops.Further, though there are no substituents in the aromatic rings otherthan bonds with other aromatic rings, superior characteristics can bemanifested by inserting such substituents as a cyano group, a halogengroup, an alkyl group or an alkoxy group as described below. Also, atleast one of the structures of the ester group shown in the firstembodiment or the group, described later, can be employed. Fluorine canalso be substituted for H in the compound.

The other element component portions, conditions for production andapplications are the same as in the first embodiment.

Third Embodiment

In this embodiment, the polymer precursors are an ester methacrylate orester acrylate derivative having two or more aromatic rings as a sidechain and at least one of the aromatic rings may be hydrogenated. Thereis an acetylene group between these aromatic rings. First, there is anexample that employs a polymer precursor having two polymerizableportions. The polymer precursor employed is di-(para-methacryloyloxyphenyl) acetylene, ##STR10## Other production conditions were the sameas in the case of the first embodiment with the liquid crystal and thepolymer undergoing phase separation.

The electro-optical characteristics of the display element were measuredaccording to the method applied in the first embodiment. The displaybegan to invert at 4 V (5% reflectivity), and the display becamesaturated at 6 V (210% reflectivity).

In another example, an acetylene compound with one polymerizable portionwas employed. Para-methacryloyloxy tolan, ##STR11## was employed. Otherthan the use of this polymer precursor, production conditions were thesame as in the case of the first embodiment.

The electro-optical characteristics were measured according the methodof the first embodiment. The display began to invert at 3.5 V (5%reflectivity), and the display became saturated at 5.5 V (200%reflectivity).

In a further example, a polymer precursor having two acetylene bonds andcontaining no alkyl side chain was employed. The element was producedaccording to the conditions of the first embodiment. Here,1-(4'-methacryloyloxy phenyl)-4-phenyl-1,3-butadiene, ##STR12## wasemployed.

Next, the electro-optical characteristics of the element were measuredaccording to the same method as in the case of the first embodiment. Thedisplay began to invert at 3.5 V (5% reflectivity), and the displaybecame saturated at 5.5 V (200% reflectivity).

The skeleton formula for the polymer precursor employed in thisembodiment may be written as: ##STR13## where, X, Y are substituents, l,m are positive integers (including zero),

n is a positive number, and

R is H or CH₃.

in the case of two polymerizable portions, and as: ##STR14## where, X, Yare substituents, l, m are positive integers (including zero),

n is a positive number, and

R is H or CH₃.

in the case of one polymerizable portion. Combinations of X, Y, l, m andn make it possible to use various different kinds of compounds. Forexample, assuming n=2, two acetylene skeletons may be joined. When n isplural, X is repeated a plural number of times, but, of course, theskeleton can be changed each time. The same is true with m. In additionto aromatic rings and an acetylene skeleton, the polymer precursor mayhave a skeleton that increases the index of refractive anisotropy.Further, these polymer precursors may be mixed with other polymerprecursors, e.g., single-function polymer precursors, such as, biphenylmethacrylate. The polymerizable portion may be acrylic, methacrylic,crotonic acid, fumaric acid, maleic acid, a vinyl group, an epoxy groupor other polymer group. Of course, R in the chemical formula may be analkyl group or other substituent. Also, a polymer precursor with apolymerizable portion that is hardened by means of heat or an electronbeam may be employed. Regarding the aromatic rings, at least one can behydrogenated. The aromatic rings are not limited to phenyl groups, asbiphenyl, terphenyl, naphthalene, anthracene and other polycyclicaromatic rings can be employed. Para-substitution was used as thesubstitution mode for the aromatic rings, but they will function as anelement with meta-substitution or ortho-substitution. However, thedegree of scattering readily drops. Further, though there are nosubstituents in the aromatic rings other than bonds with other aromaticrings, superior characteristics can be manifested by inserting suchsubstituents as a cyano group, a halogen group, an alkyl group or analkoxy group as described below. Also, at least one of the structures ofthe ester group, amide group or urethane group, described later, can beemployed. Fluorine can also be substituted for H in the compound.

In this embodiment, two-function and single-function polymer precursorswere shown, but by mixing two-function polymer precursors withsingle-function polymer precursors, a display element with a low drivevoltage and good heat resistance and durability can be produced.

Fourth Embodiment

This embodiment demonstrates an example in which the polymer precursoris an amide of acrylic acid or methacrylic acid. Biphenyl methacrylicamide, ##STR15## was employed as the polymer precursor and the elementwas produced under the same conditions as in the third embodiment.

The electro-optical characteristics of the element were measuredaccording to the method used in the first embodiment. The display beganto invert at 3.5 V (5% reflectivity), and the display became saturatedat 5 V (180% reflectivity).

N-methyl biphenyl methacrylic amide, or the like, may also be used asthe polymer precursor.

As shown by the formula, ##STR16## where, P includes an aromatic ring,and R, R₁ are H or CH₃,

the side chain may have an aromatic ring. Even in the case where thereare plural aromatic rings, the display element will function. Even inembodiments other than this embodiment, if the ester group that bondsthe polymer part and the side chain is changed to an amide group, it cansimilarly be used as a polymer precursor. The display element can beproduced. The aromatic rings are not limited to phenyl groups, andbiphenyl, terphenyl, naphthalene, anthracene and other polycyclicaromatic rings can be used. Para-substitution was used as thesubstitution mode for the aromatic rings, but they will function as anelement with meta-substitution or ortho-substitution. Though there areno substituents in the aromatic rings other than bonds with otheraromatic rings, superior characteristics can be manifested by insertingsuch substituents as a cyano group, a halogen group, an alkyl group oran alkoxy group as described below. Also, at least one of the structuresof the ester group, amide group, urethane group or acetylene group,described later, can be employed. Fluorine can also be substituted for Hin the compound. The polymerizable portion may be acrylic, methacrylic,crotonic acid, fumaric acid, maleic acid, a vinyl group, an epoxy groupor other polymer group. The R in the chemical formula may be an alkylgroup or other substituent. Also, since N is included in this compound,H, CH₃, an alkyl group or other substituent can be introduced for N orit may be a polymerized substituent.

Fifth Embodiment

This embodiment demonstrates an example wherein a cyano group, a halogengroup or an aromatic ring are bonded directly or indirectly to thearomatic ring contained in the polymer precursor. As shown by theformula, ##STR17## where, R is H or CH₃, and X is CN, F, Cl, Br, I or anaromatic ring (may contain other elements),

a polymer precursor is employed wherein a cyano group, a fluoro group, achloro group, a bromo group, an iodine group or an aromatic ring issubstituted for biphenyl methacrylate. The liquid crystal material,substrate and production conditions, and measurement conditions wereproduced under the same conditions as in the case of the firstembodiment. As to electro-optical characteristics, the display conditionbegan to invert at 3 V (5% reflectivity) and became saturated at 5 V(200% reflectivity) when a cyano group was substituted. When a halogengroup was substituted, the reflectivity was improved over that withoutsubstitution, and the electro-optical characteristic was improved in thefollowing order: iodine group (195% reflectivity)>bromo group (190%reflectivity)>chloro group (185% reflectivity)>fluoro group (180%reflectivity). When a phenyl group was substituted, an extremely brightdisplay was achieved having 220% reflectivity.

Para-substitution was used as the substitution mode for the aromaticrings, but they will function as an element with meta-substitution orortho-substitution. In addition to a phenyl group, the basic skeletonformula of the polymer precursor employed here may be biphenyl,terphenyl, naphthalene, anthracene or other polycyclic aromatic ring orthe basic skeleton formula of an embodiment other than this embodimentfor the aromatic ring. For example, ##STR18## where, P₁, P₃ containaromatic rings, the part in parentheses may be bonded in reverse,

R is H or CH₃, and

X is CN, F, Cl, Br, I or an aromatic ring (may contain other elements),##STR19## where, P₁, P₃ contain aromatic rings, A is OCONH or NHCO andmay be bonded in reverse,

R is H or CH₃, and

X is CN, F, Cl, Br, I or an aromatic ring (may contain other elements),##STR20## where, P₁, P₃ contain aromatic rings, B includes an acetyleneskeleton,

R is H or CH₃, and

X is CN, F, Cl, Br, I or an aromatic ring (may contain other elements),or ##STR21## where, P₃ contains an aromatic ring, R, R₁ are H or CH₃,

X is CN, F, Cl, Br, I or an aromatic ring (may contain other elements).

The substituents, shown here, may be inserted directly or indirectly,and their number is not limited to just one. Also, including differenttypes of the ester groups, amide groups, urethane groups and acetylenegroups, shown here, may be included as two or more. In other words, allof the compounds shown in this invention may be employed as a basicpolymer precursor. Also, the substitution mode is not limited topara-substitution, and meta-substitution or ortho-substitution can used.Of course, the same effect is manifested even if plural types ofsubstituents are introduced. When an aromatic ring is used as asubstituent, one or more, or one or more types, of substituents, suchas, those shown here, alkyl groups or alkoxy groups, may be substituteddirectly or indirectly for the aromatic ring. Also, a mixture of thepolymer precursors shown here or the polymer precursors shown in otherembodiments can be employed. Here, the polymerizable portion may beacrylic, methacrylic, crotonic acid, fumaric acid, maleic acid, a vinylgroup, an epoxy group or other polymer group. The R in the chemicalformula may be an alkyl group or other substituent. Since N may becontained in a chemical formula above, H, CH₃, an alkyl group or othersubstituent may be introduced as N or it may be a polymer substituent.

Sixth Embodiment

This embodiment demonstrates an example wherein a polymer precursorcontaining fluorine is employed. Pentafluorobenzoyloxy phenylmethacrylate, ##STR22## was used as the polymer precursor, and theliquid crystal, substrate and production conditions were produced underthe same conditions as in the case of the first embodiment. Measurementsof the electro-optical characteristics illustrated that the displaycondition began to invert at 3.3 V (5% reflectivity) and becamesaturated at 4.6 V (200% reflectivity).

The polymer precursor employed may be a compound with a fluorine in theother polymerizable portion of the example, shown above; e.g., ##STR23##where Y1, Y2, Y3 and R are substituents.

In the case here, at least one of Y1, Y2 and Y3 contain fluorine, and itis desirable to use H, F, CH₃, CF₃ or other alkyl group, but othersubstituents may be employed. R should be an ester substituentcontaining at least one or more phenyl groups. For example, --CO₂ --C₆F₄ --C₆ F₅, --CO₂ --C₆ F₄ --C₆ F₄ --OCO--C₆ F₅ (F can be partially H orother substituent, e.g., phenyl group, or the like may be employed. Theester group may be bonded in reverse. It is more desirable that fluorinebe substituted for this phenyl group. In addition to an estersubstituent, R may be an ether substituent, an alkyl substituent, or thelike. However, it is important to select one whose index of refractionis close to that of the liquid crystal. Also, regarding the fluorinesubstituent and the substituent location, it is desirable to make thepolymer precursor and liquid crystal compatible before polymerization,and, then, select the amount of fluorine substituent and the substituentlocation after polymerization such that the liquid crystal and dichroicdye do not become compatible. R may contain the polymer location shownabove; i.e., there may be plural polymerizable portions in one compound.For example, compounds, such as, ##STR24## may be employed. In the caseshown here wherein all of the substitution modes of the benzene ringwere at the para position, the meta position and ortho position may alsobe used. Further, a mixture of these polymer precursors or other polymerprecursors, e.g., biphenyl acrylate, can be employed. The polymerizableportion may be acrylic, methacrylic, crotonic acid, fumaric acid, maleicacid, a vinyl group, an epoxy group or other polymer group. Polymersthat may undergo ultraviolet polymerization or electron beampolymerization or heat polymerization may be employed.

Seventh Embodiment

This embodiment demonstrates an example wherein an alkyl group or analkoxy group is substituted either directly or indirectly for thearomatic ring as the polymer precursor.

First, an example is shown that uses a polymer precursor with an alkoxygroup on the aromatic ring in the first embodiment. Other than thepolymer precursor, the display element produced under the sameconditions as in the case of the third embodiment. Here,4-(4'-benzoyl)phenyl methacrylate, ##STR25## was employed as the polymerprecursor. When the electro-optical characteristics were measured usingthe same method according to the first embodiment, the display began toinvert at 3 V (5% reflectivity) and became saturated at 4.5 V (200%reflectivity). The transmissive type display had a similar effect.

As another example, a polymer precursor with an alkyl side chain on thearomatic ring in the first embodiment was employed. Other than thepolymer precursor, the display element was produced under the sameconditions as in the case of the third embodiment. Here,4-(4'-pentylbenzoyl) phenyl methacrylate, ##STR26## was employed as thepolymer precursor. When the electro-optical characteristics weremeasured according to the same method as in the first embodiment, thedisplay began to invert at 3 V (5% reflectivity) and became saturated at4.4 V (200% reflectivity).

As a further example, an alkyl chain is bonded to the basic skeletonformula shown in the second embodiment. Here, 4-methacryloyloxyphenyl-4'-butoxy phenylcarbamate, ##STR27## was employed as the polymerprecursor. The display element was produced under the same conditions asin the case of the first embodiment. The electro-optical characteristicsof the element were measured according to the method of the firstembodiment. The display began to invert at 3.4 V (5% reflectivity), andthe display became saturated at 4.8 V (180% reflectivity).

In a further example, an alkoxy group is bonded to the basic skeletonformula shown in the third embodiment. The display element was producedunder the same conditions as in the case of the first embodiment. Here,4-methacryloyloxy-4'-hexyloxy tolan, ##STR28## was employed as thepolymer precursor. The electro-optical characteristics of the elementwere measured according to the method of the first embodiment. Thedisplay began to invert at 3.4 V (5% reflectivity), and the displaybecame saturated at 5.4 V (200% reflectivity).

As a further example, an alkyl group or an alkoxy group are indirectlybonded to the aromatic ring: ##STR29## where, R is H or CH₃, P₄ includesan aromatic ring,

D is an ester, ether, amide or alkyl chain, and

R₂ is an alkyl group or alkoxy group.

Here, the group that bonds the aromatic ling and the alkyl group is anester, ether, amide or alkyl chain. The characteristics do notsignificantly change depending on the structure of this position.

With the employment of the polymer precursor in this embodiment, thethreshold voltage can be lowered while, at the same time, thereflectivity is improved by introducing an alkyl group or an alkoxygroup. The compounds shown in all of the embodiments of this inventionmay be used as basic polymer precursors. As to the length of the alkylgroup or alkoxy group, lengths up to nine carbon atoms have been tested,and their operation in conjunction with a display element has beenconfirmed. When the alkyl group or the alkoxy group is too long, thereflectivity rises and the contrast suffers. Three to six carbon atomsare desirable, and they may either be bonded directly to the aromaticring or bonded via an ether bond, ester bond or other hetero atom.Regarding the substitution position, all experiments were performed withpara substitution, but the same effect can also be expected withmeta-substitution or ortho-substitution. Also, there are cases in whichsubstitution on the alkyl group or alkoxy group can be performed with ahalogen atom, a cyano group or other atom or group with a large dipolemoment. These substituents may be substituted on plural aromatic rings.Here, the polymerizable portion may be acrylic, methacrylic, crotonicacid, fumaric acid, maleic acid, a vinyl group, an epoxy group or otherpolymer group. The CH₃ of the methacrylic group in the chemical formulamay an alkyl group or other substituent.

Eighth Embodiment

This embodiment demonstrates an example wherein the polymer precursor isoptically active element. The polymer precursor used was4'-(2"(S)-methyl propyloxy)biphenyl-4-methacrylate, ##STR30## and theliquid crystal material, element and production conditions were producedunder the same conditions as in the case of the first embodiment. Theelectro-optical characteristics of the element were measured. Thismeasurement showed that the display condition began to invert at 3 V (5%reflectivity) and became saturated at 5 V (200% reflectivity).

Even if the polymer precursor is other than that employed in thisembodiment, the same effect can be demonstrated, as long as it isoptically active. For example, precursors that satisfy the generalformula, ##STR31## where, R is H or CH₃, P₅ is optically active andincludes an aromatic ring, and

Z is O or N.

e.g., 4-(2'(S)-methyl propyloxy)phenyl methacrylate, ##STR32## can beemployed. In other words, substituents with a chiral center may beintroduced in the compounds of all of the embodiments of the invention.The substitution mode used here for the aromatic ring was parasubstitution, but meta substitution or ortho substitution may also beemployed. Also, substitution can be performed at the same time withanother substituent. An optically active polymer precursor may beemployed as one component of the polymer precursor. Here, thepolymerizable portion may be acrylic, methacrylic, crotonic acid,fumalic acid, maleic acid, a vinyl group, an epoxy group or otherpolymer group. The R in the chemical formula may be an alkyl group orother substituent.

In a further example, an optically active polymer precursor is usedcomprising a 1:1 ratio mixture of 4'-(2"(S)-methylpropyloxy)biphenyl-4-methacrylate and 4-biphenyl methacrylate wasemployed as the polymer precursor. The remaining configuration andproduction method and conditions were according to those in the firstembodiment.

The element produced in this manner demonstrated a characteristicbetween that of the previous example of this embodiment and a prior artexample. The molecular rotary power of the optically active polymerprecursor differs depending on its skeleton formula. Since the drivevoltage increases if the molecular rotary power becomes too large, it isnecessary to dilute with an optically active polymer precursor as is thecase here.

An optically S material was employed as the optically active material inthis embodiment, but an optically R material may also be similarlyemployed. Also, though a chiral component was not included in the liquidcrystal used here, a chiral component can be mixed in the compound toimprove contrast and brightness of the display.

Ninth Embodiment

This embodiment demonstrates an example where a two-function polymerprecursor and a single-function polymer precursor are mixed together.The polymer precursor used here was a mixed in a ratio of 2:1 of cyanobiphenyl methacrylate and phenyl di-methacrylate, ##STR33## The mixratio is not limited to that above. The liquid crystal, element andproduction conditions were the same as in the first embodiment. By thismeans, the thermal resistance and reliability of the electro-opticalconditions were improved without sacrificing the characteristics of thesingle-function polymer precursor. Moreover, in the prior art case, thepolymer grains melt at 100° C., but in the case here, polymer grains donot melt up to 120° C. The same effect was observed relative to thepolymer precursors in all the embodiments of this invention. Thetwo-function polymer precursors that may be mixed with thesingle-function polymer precursor include, ##STR34## the compound shownin FIG. 3, and polymer precursors that have a liquid crystal phase, suchas, ##STR35## used by Hikmet, et al., and compounds, such as, ##STR36##with a bis-phenol A skeleton formula. In this case, an aromatic ringneed not necessarily be included. For example, an acrylic or methacrylicgroup can be attached at either end of the alkyl chain, such as,##STR37## R is H or CH₃, and n is a positive number.

Here, the polymerizable portion may be acrylic, methacrylic, crotonicacid, fumaric acid, maleic acid, a vinyl group, an epoxy group or otherpolymer group. The R in the chemical formula may be an alkyl group orother substituent. Also, the polymer precursor need not have twofunctions, but, rather, may be a multifunction polymer precursor withthree or more functions, e.g., product No. M7100 available from ToaGosei K K.

Tenth Embodiment

This embodiment demonstrates an example in which two types of polymerprecursors are employed. The same substrate as in the first embodimentwas used. Here, the precursors 4-benzoyloxy phenyl methacrylate andmethacryloloxy phenyl-4'-methyl phenylcarbamate, ##STR38## were employedand were mixed in a ratio of 1:1 (W:W). The display element was producedunder the same conditions as in the case of the first embodiment.

The electro-optical characteristics of the element were measuredaccording to the method of the first embodiment. The display began toinvert at 3.5 V (5% reflectivity), and became saturated at 5 V (180%reflectivity).

When two or more types of polymer precursors are mixed, the polymerprecursors relative to all of the embodiments of this invention may beemployed as the mixed precursors. Also, the amounts mixed and thecomposition ratio with liquid crystal are not limited by this embodimentand must be optimized as required. Multifunction polymer precursors,such as those in the ninth embodiment, may be mixed with asingle-function polymer precursor mixture such as employed in thisembodiment. The polymerizable portion may be acrylic, methacrylic,crotonic acid, fumaric acid, maleic acid, a vinyl group, an epoxy groupor other polymer group.

Eleventh Embodiment

This embodiment demonstrates an example employing a substrate havingundergone vertical alignment treatment. A cross section of the displayelement according to this embodiment is illustrated in FIG. 2. Theproduction method for the display element for this embodiment isexplained below. The surface of the substrate undergoes verticalalignment treatment and ,except for the liquid crystal, product No.RDP00775, available from Rodic Company, containing very little or nocomponent and having a negative dielectric anisotropy, the liquidcrystal is the same as that employed in the first embodiment.

The polymer precursor employed is 4'-fluoro-biphenyl methacrylate,##STR39##

The electro-optical characteristics of the element were measuredaccording to the method of the first embodiment. However, anon-directional reflective plate is used as the reflective plate. At 7V, the display began to invert (100% reflectivity), and the displaybecame saturated at 15 V (10% reflectivity). Since the characteristic isreversed from that of horizontally aligned type of displays, the displayelement should be expected to satisfy other different applications. Itcan be used in transmission types and can be applied to light bulbs. Thepolymer precursor employed here is only representative of the polymerprecursors of this invention, as any of the polymer precursors provideis this invention may be employed. The liquid crystal may also bedifferent from the one employed here as long as it has a large An valueand has a negative dielectric anisotropy. Also, the display elementfunctions as a display element whether or not a dichroic dye is includedin the mixture.

Twelfth Embodiment

This embodiment demonstrates an example wherein the direction ofalignment of the polymer is inclined with respect to the substratesurface. FIG. 3 is a cross section of the display element according tothis embodiment. The production method of the display element isexplained below. Product No. JAS23 and product No. JIB, both of whichare available from Nihon Gosei K K, were mixed in a ratio of 1:1, wereapplied relative to a pre-tilt alignment treatment accomplished on thesurfaces of substrates 1 and 6 on which electrodes 2 and 5 were formed.The mixture then underwent horizontal alignment treatment after drying.Except for the substrate alignment preparation, the display element ofthis embodiment was produced under the same conditions as in the case ofthe first embodiment.

The display began to invert at 3 V (5% reflectivity) and becamesaturated at 4 V (170% reflectivity). Thus, as can be seen, the drivevoltage is comparatively lower. The polymer precursor employed here isonly representative of the polymer precursors that may be employed, asany of the other polymer precursors of this invention may also beemployed. Also, the substrate treatment of this embodiment can beapplied in connection with all of the embodiments of this invention.

Thirteenth Embodiment

In this embodiment, an example is demonstrated wherein a polymerprecursor described above was employed. Product No. RDP00536, availablefrom the Rodic Company, which has a high resistance, was employed as theliquid crystal, product No. S-1011, available from Merck Co., isemployed as the chiral component, and product No. S-344, available fromMitsui Toatsu Senryo K K, is employed as the dichroic dye. Further,active elements are employed on the element substrate. First, productNos. S-1011 and S-344 were mixed with liquid crystal, product No.RDP00536, in ratios of 0.5% and 1.5%, respectively, and, then,4-benzoyloxy phenyl methacrylate, employed in the first embodiment andtetrafluoro-di-phenyl methacrylate were mixed in ratios of 8% and 2%,respectively.

FIG. 4 shows a partial cross section of the display element according tothis embodiment utilizing MIM elements as active elements. ITO wasformed for transparent electrode 2 on substrate 1, and then alignmenttreatment was applied to the surface. After a tantalum layer was formedon substrate 6, the surface was oxidized to form insulation layer 8, onwhich reflective picture element electrodes 9, receiving non-directionalreflectivity treatment as required, were formed. A protective layer maybe formed on the element surfaces to protect the active elements. Thissurface is then subjected to an alignment treatment. Substrate 1 andsubstrate 6 were separated by a gap of about 5 μm with the electrodesurfaces of the substrates were in facing relationship. Then, substrates1 and 6 were fixed in position such that the directions of alignmentapplied on the upper and lower substrates were substantially parallel.

In the embodiment here, the active element substrate underwentreflectivity treatment and the opposing substrate was made transparent,but the opposing substrate may undergo reflectivity treatment and theelement substrate may be made to be transparent. Also, though thereflective layer and the electrodes were formed as one unit here, theelectrodes and reflective layer may be formed separately.

The mixed liquid crystal components, described above, were then injectedinto the empty panel space, and the polymer precursors were polymerizedby ultraviolet light irradiation whereby the liquid crystal and polymerwere phase separated.

A signal, having a selection period of 60 μm and a non-selection periodof 16 ms, was utilized for driving the MIM element produced according tothis embodiment, the display element inverted at a signal peak value of35 V with 150% reflectivity. The reason for the low reflectivitycompared with the previous embodiments is because the numerical apertureof the active element substrate was only 70%.

Any type of liquid crystal may be employed as long as the material hashigh retention, has a generally high resistivity, e.g., greater than1×10¹⁰ Ω·cm, has a large dielectric constant, and has a largebirefringence value.

The chiral component is not limited to the one employed in thisembodiment as a polymer precursor with a chiral center, such as, thatpresented in the eighth embodiment, may be employed here as the chiralcomponent. Also, the mix ratio is not limited to that employed, but iftoo much chiral component is included, there is a tendency for thehysteresis to increase and raise the drive voltage.

The dichroic dye should have little absorption in the ultraviolet bandand have a large dichroic ratio. The color of the dye can be selectedaccording to the desired application. The amount of dye contained is notlimited to the amount used here, but if too much is included, the dyemay crystallize or darken the display.

A polymerization initiator was not employed in this embodiment, but onemay be employed together with an optical sensitizer. However, careshould be taken as the resistivity tends to easily drop in value.

Any of the polymer precursors according to all of the embodiments ofthis invention may be employed as the polymer precursor in thisembodiment. In particular, if two-function or multifunction polymerprecursors are mixed, display burn-in, upon manufacture of the display,or other such treatment, is not easily accomplished, even if the polymerprecursor content is reduced. The content of polymer precursor need notbe that utilized in this embodiment. However, if the content of theprecursor is too small, light scattering is reduced. If the content ofthe precursor is too large, the drive voltage is increased.

The polymerization conditions may be those of the first embodiment.However, polymerization should be done with care since the resistivitycan easily drop in value. A light intensity of 3 MW/cm² was used, butother intensity values may be employed. If the light intensity isreduced, the polymerization time is lengthened, and if the lightintensity is increased, the polymerization time is shortened. However,if the light intensity is too strong, the resistivity drops in value.Polymerization is simplified if some slight heating, such as in therange of 20° to 50° C., is applied at the time of photopolymerization.

Aluminum was employed for the reflective electrodes, but silver, nickel,chrome, and the like may be employed for the electrodes as long as theyare capable of reflecting light. Also, the electrodes can be madetransparent and reflective back plate may be utilized on the backside ofthe display element.

MIM elements were employed in this embodiment as the active elements,but TFT elements or other elements capable of driving liquid crystalmaterial may be employed.

Alignment treatment may be performed by any method that orients theliquid crystal. As shown in the twelfth embodiment, the liquid crystalmay be inclined with respect to the substrate surface. Verticalalignment treatment may also be employed. However, in this case, aliquid crystal with a negative dielectric anisotropy must be employed.The direction of alignment treatment may be optimized depending on theapplication since the resulting direction of distinct visibilityaccordingly changes.

In this embodiment, reflectivity treatment need not be performed, andthe element may be used as a transmissive type display element or alight control valve if the dichroic dye is not included in the liquidcrystal mixture.

Fourteenth Embodiment

In this embodiment, an example is provided wherein a color filter isemployed in conjunction with active elements. FIG. 5 is a partial crosssection of a color display element that employs TFT elements as theactive elements. In practice, picture elements corresponding to eachcolor like those shown here are arranged in a mosaic or lattice. Liquidcrystal 4 and polymer layer 3 of the thirteenth embodiment may beemployed in this embodiment. In fabrication of a display element, first,gate electrodes 11 were formed on substrate 6, followed by gateinsulation layer 14, semiconductor layer 12, drain electrodes 13, sourceelectrodes 10 and picture element electrodes 9 were formed. Theelectrodes 9 may undergo non-directional reflectivity treatment ifrequired. A protective layer may be formed on picture element electrodes9 in order to protect the active elements. The top of picture elementelectrodes 9 then underwent alignment treatment. Next, color filter 15was formed on opposing substrate 1, followed by transparent electrode 2.Then, the surface of electrode 2 underwent alignment treatment.

As described above, the two substrates with electrodes are, then, matedtogether such that the liquid crystal layer is about 5 μm thick. Theliquid crystal layer need not be 5 μm, but if this spacing is too thick,the drive voltage increases and the TFT elements are not capable ofdriving the alignment of the liquid crystal. Here, the active elementsubstrate underwent reflectivity treatment, but, alternatively, theopposing substrate may undergo reflectivity treatment. Also, the colorfilter may be positioned on the front side or on the reflectivesubstrate side of the display element. The color filter may also bepositioned between the substrates or between the electrodes and theliquid crystal layer.

A mixture of liquid crystal corresponding to the display mode andpolymer precursors employed was provided in the gap and an externalelectric field is applied to orient the mixture.

The liquid crystal, polymer precursor, dichroic dye, chiral componentand the production conditions employed in this embodiment may be thesame as those in the thirteenth embodiment.

In this embodiment, reflectivity treatment need not be performed, andthe element may be employed as a transmissive type display element or alight control valve if the dichroic dye is not included.

This embodiment permits the production of a full color, reflective type,large capacity color display element.

In addition to TFT elements and MIM elements, TFT and MIM elements withconfigurations different from those illustrated in the foregoingembodiments may be employed as the active elements. In this regard,active elements employing ferroelectric material may also be employed asan active element.

Fifteenth Embodiment

In this embodiment, an example is demonstrated that employs, as apolymer precursor, a polymer compound having an epoxy group as at leastone component. In this example, ##STR40## was employed, and the displayelement was produced with the same materials and production methods aswere employed in conjunction with the first embodiment. However, inaddition, 5% of the product No. SP-150, available from Asahi Denka KogyoK K, was employed with the polymer precursor as a polymerizationinitiator. The display element produced in this manner provided the samecharacteristics as in the case when methacrylic or acrylic polymer,utilized in previous embodiments, were employed, i.e., the displaycondition began to invert at 3.5 V and the display condition inverted at5 V.

The polymer precursor employed in this embodiment is a compound of aprevious embodiment having a polymerized portion comprising an epoxygroup and principally represented by the following compounds, ##STR41##where, P₁ and P₃ include aromatic rings, E includes an ester group,urethane group, amide group, acetylene group, and

X is H, CN, F, Cl, Br, I, aromatic ling, alkyl group or alkoxy group(may contain other elements), ##STR42## where, X, Y are substituents, l,m are positive integers (including zero), and

n is a positive number, ##STR43## where, X, Y are substituents, l, m arepositive integers (including zero), and

n is a positive number, ##STR44## where, X is H, CN, F, Cl, Br, I, anaromatic ring (which may contain other elements), and

multiple biphenyl groups may be substituted at X, ##STR45## where, thebiphenyl group may have a substituent group, and the biphenyl group maybe a phenyl group, ##STR46##

Z in the chemical formula is either O or N. If Z is N, one more epoxygroup or side chain may be inserted. In the cases here, the compoundsmost commonly derived from epichlorohydrin as epoxy groups areillustrated, but any type of substituent may be included as long as anepoxy group is introduced. Also, an alkyl, an ethyl, an ester, an amideor a urethane group may be utilized as a spacer between the epoxy groupand the aromatic ring. The electro-optical characteristics of thedisplay element when utilizing the compounds illustrated here hadcharacteristics similar to the results achieved in the previousembodiments, but the overall drive voltage tended to be higher.

A sensitizer or a polymer medium may be used as a photopolymerizationinitiator in addition to product Nos. SP-150, SP-170, UVE-1014 andUVE-1016, available from General Electric Co., and product Nos. CyracureUVI-6974 and UVI-6990, available from UCC, or other such materialsfunctioning as an initiator when the epoxy resin is hardened by means oflight. The mixing ratio can be a small amount because the initiator actsas a catalyst to the polymer precursor. Since the absolute amount variesdepending on the polymer precursor, it should be optimized as theapplication requires. If the mix ratio is too high, however, theresistivity of the element drops and its reliability is also degraded.

Sixteenth Embodiment

In this embodiment, an example is demonstrated wherein the polymerprecursor employed in the previous embodiment is polymerized in advanceand is made compatible with the liquid crystal by heating, and thepolymer was precipitated from the liquid crystal by cooling.

The polymer precursor employed was 4-benzoyloxy phenyl methacrylate andthe liquid crystal was a combination of product No. TL202, availablefrom Merck Co., together with product No. CB15, available from BDHCompany, as the chiral component, and product No. S-428, available fromMitsui Toatsu Senryo K K, as the dichroic dye. First, the polymerprecursors were polymerized by ultraviolet light to form the polymerwherein they were heated to 120° C. to render them compatible with theliquid crystal, and then they were inserted between twoelectrode-equipped substrates that had undergone alignment treatment.The final display element was cooled at a rate of 1° C./min. to providefor precipitation of the polymer in an aligned state. The slower coolingrate is performed, the better. If cooling is accomplished too fast, thepolymer grains are precipitated out of solution without being aligned.

In this embodiment, the element will function as long as the ratio ofpolymer to liquid crystal is in the range between 3:97 and 50:50. Also,the chiral component and dichroic dye need not be included in themixture. Other than those shown here, the polymer precursors, liquidcrystal, chiral component, and dichroic dye, as applied in previousembodiments, may be employed. In this embodiment, two substrates wereemployed, but the display element may be produced by applying the aboveto one substrate and treating them similarly and then forming theopposing electrode. It is also possible to fabricate a display elementby mating separate substrates on which liquid crystal polymer layershave been formed. Also, active elements may be employed in one of thesubstrates, as previously illustrated in conjunction with FIGS. 4 and 5,whereby large capacity display panels can be realized. It is alsopossible to include a color filter, as illustrated in a previousembodiment, to provide a color display.

Seventeenth Embodiment

In this embodiment, an example is demonstrated wherein the polymerprecursor employed in the previous embodiment is polymerized in advanceand, further, is made compatible with the liquid crystal throughheating, after which the polymer is precipitated out of the liquidcrystal by means of cooling.

The polymer precursor used was 4-(p-pentylbenzoyloxy) phenylmethacrylate and a combination comprising liquid crystal, product No.MJ90657, available from Merck Co.; chiral component, product No. CM20,available from Chisso K K; and a dichroic dye, product No. S-344,available from Mitsui Toatsu Senryo K K, which are mixed together.Initially, the polymer precursors were polymerized by ultraviolet lightto form the polymer. The polymerized polymer precursor and the liquidcrystal were then made compatible employing methyl ethyl ketone as asolvent. The mixture was then spread out on an electrode-equippedsubstrate that had previous undergone alignment treatment. Thisstructure was, next, dried by heating at 50° C. to remove the solvent,and the polymer was precipitated out in an aligned state. Next, anopposite electrode-equipped substrate was mated with this preparedpolymerized polymer precursor substrate to form a display element.

If the aligned state of the precipitated polymer appears to be in a poorstate, a heating-cooling process, such as utilized in the sixteenthembodiment may be performed after the solvent has been removed.

In this embodiment, the element will function as long as the ratio ofpolymer to liquid crystal is in the range between 3:97 and 50:50. Thechiral component and dichroic dye need not be included in the mixture.Macromolecule precursors, liquid crystal, chiral component, and dichroicdye employed in previous embodiments may also be employed in thisembodiment. While two substrates were used in this embodiment, thedisplay element may be produced by applying to one substrate, theprepared polymerized polymer coating after which the opposing electrodesare formed. It is also possible to make a display element by matingsingle substrates on which liquid crystal polymer layers have beenrespectively formed. Also, active elements may be employed on theprepared polymerized polymer substrate whereby a large capacity displayelement can be realized. It is also possible to combine a color filter,as illustrated in a previous embodiment, to produce a color display.

Eighteenth Embodiment

In this embodiment, an example is demonstrated in FIG. 6 wherein,relative to the substrates that provide alignment of the liquid crystaland polymer, direction 16 of alignment treatment of at least thesubstrate on the light incident side of the display element isperpendicular to the plane containing principal direction 18 of incidentlight and also normal relative to direction 19 of the substrate. In FIG.6, a reflector plate 6 is also employed on the back of the displayelement. In this embodiment, however, direction 16 of alignmenttreatment is also applied to the rear substrate as well as to the frontsubstrate. Also, for the sake of example comparison, an example is shownwherein the display element is disposed having a direction of alignmenttreatment rotated 90° with respect to the direction of alignmenttreatment of this embodiment. The configurations and production methodsemployed in other embodiments of this invention may be employed relativeto the display element of this embodiment. The electro-opticalcharacteristics of a display element according to this embodiment,including a polymerized polymer/liquid crystal mixture together with adichroic dye and chiral component, are illustrated in FIG. 7. The solidline in FIG. 7 relates to this embodiment while the dashed line relatesto the comparison example. As shown in FIG. 7, the electro-opticalcharacteristics of this embodiment are improved by about 30% over thecomparison example. In addition to making the direction of alignmenttreatment on the rear substrate the same as on the front substrate, aneffect like that illustrated here can be achieved by choosing any otherdirection.

Nineteenth Embodiment

In this embodiment, reference is made to FIGS. 8 and 9 illustrating anexample wherein a optical phase shift plate 21 and a reflective plate ora light scattering plate 20 are disposed on the back of substrates thatinclude a layer of liquid crystal and polymer previously aligned anddispersed in the layer. FIG. 8 shows an example wherein the liquidcrystal and polymer are aligned horizontally with respect to thesubstrate surface, and FIG. 9 shows an example wherein the liquidcrystal and polymer are aligned perpendicularly with respect to thesubstrate surface.

The principal involved is illustrated employing a 1/4-wavelength plateas the optical phase shift plate 21 in a system in which a dichroic dyeis mixed with the liquid crystal and the polymer, but a chiral componentis not employed.

First, in FIG. 8, the vertically and horizontally polarized componentsof the incident light 18 are considered separately. The liquidcrystal/polymer layer 17 is aligned in horizontal direction 16. Also,the direction of alignment of 1/4-wavelength plate 21 is disposed suchthat it is inclined 45° with respect to the direction of alignment ofthe liquid crystal/polymer layer.

In the case of FIG. 8A, with no electric field applied, verticallypolarized light is not absorbed by the dichroic dye, passes throughliquid crystal/polymer layer 17, passes through 1/4-wavelength plate 21,is reflected or scattered at plate 20, and passes again through1/4-wavelength plate 21, whereby its polarization plane is rotated 90°.Therefore, absorption by the dichroic dye in the liquid crystal/polymerlayer occurs this time, and the reflected, returning light is notemitted out of the front the display element. On the other hand,horizontally polarized light is absorbed by the dichroic dye in theliquid crystal/polymer layer.

In the case of FIG. 8B, with an electric field applied, absorption bythe dichroic dye is decreased. When vertically polarized light entersthe display element this time, it passes through the liquidcrystal/polymer layer, passes through 1/4-wavelength plate 21, isreflected or scattered by light scattering plate 20, and passes againthrough 1/4-wavelength plate 21, whereby its polarization plane isrotated 90°. Therefore, this time the light is scattered in the liquidcrystal/polymer layer with light exiting from the display element. Whenhorizontally polarized light enters the display element, lightscattering occurs in the liquid crystal/polymer layer with light exitingfrom the display element. By this means, all of the polarized light,i.e., natural light, can be effectively modulated by the displayelement.

In FIG. 9, liquid crystal/polymer layer 17 is vertically aligned asindicated at 16, where incident light enters layer 17, and at 22, wherereturning light enters layer 17, and is only slightly inclined towardhorizontal direction 23 with respect to the substrate surface. In FIGS.9A and 9B, 1/4-wavelength plate 21 is disposed so that it is inclined45° with respect to horizontal direction 23.

In the case of FIG. 9A, with no electric field applied, neithervertically polarized light or horizontally polarized light are scatteredand absorbed, resulting in this light being scattered or reflected backand out of the display element.

In the case of FIG. 9B, with an electric field is applied, the liquidcrystal and dichroic dye become principally aligned in horizontaldirection 23. When vertically polarized light strikes the element atthis time, it passes through liquid crystal/polymer layer 17, passesthrough 1/4-wavelength plate 21, is either scattered or reflected byplate 20, and passes again through 1/4-wavelength plate 21. Since thepolarization plane is rotated 90° at this time, the polarized light isboth absorbed by the dichroic dye in the liquid crystal/polymer layerand scattered at the liquid crystal/polymer interface. When horizontallyaligned light enters the display element, it is both absorbed by thedichroic dye in the liquid crystal/polymer layer and scattered at theliquid crystal/polymer interface. Therefore, all of the polarized light,i.e., natural light, can be effectively modulated by the displayelement.

The foregoing light modulating configuration can be applied with respectto all of the embodiments of this invention. For example, thisembodiment can be applied where a chiral component is mixed in theliquid crystal/polymer layer, or it can be applied where a dichroic dyeis not included in the liquid crystal/polymer layer, thereby increasingthe scattering strength it is also possible to combine this embodimentwith active elements to form a large capacity display or to combine theembodiment with a color filter to provide a color display.

Twentieth Embodiment

In this embodiment, shown in FIG. 10, an example is illustrated whereintwo display elements of either of the embodiments of FIGS. 8 and 9 maybe included together. In the case here, two horizontally aligned displayelements of FIG. 8 are mated together such that their alignmentdirections are perpendicular to one another, as indicated by the twoseparate arrows 16 in FIGS. 10A and 10B. With respect to the principalof operation, one more display elements replace the optical phase shiftplate and reflection plate of the nineteenth embodiment such that thedirections of alignment are perpendicular to one another, and thecombined display element operates in the same manner as that embodiment.In other words, since the scattering characteristic of the displayelement of the invention in which there is no or very little chiralcomponent is dependent on polarization when an electric field isapplied, the polarized light, which passes through the first displayelement without being scattered, is scattered by the second displayelement, which is disposed such that it does scatter light, whereby allpolarized light, i.e., natural light, can be effectively modulated.

The foregoing light modulating configuration can be applied with respectto all of the embodiments of this invention. For example, thisembodiment can be applied where a chiral component is mixed in theliquid crystal/polymer layer, or it can be applied where a dichroic dyeis not included in the liquid crystal/polymer layer, thereby increasingthe scattering strength it is also possible to combine this embodimentwith active elements to form a large capacity display or to combine theembodiment with a color filter to provide a color display.

The compounds shown in all the foregoing embodiments can be mixed withcompounds set forth in other embodiments and employed in otherembodiments. In many cases, the resulting electro-opticalcharacteristics are midway between the electro-optical characteristicsachieved when the respective compounds are separately employed.

When a non-reflective layer or a reflective scattering layer is providedon the display element back surface relative to all of the foregoingembodiments, the resulting display provides an easier view.

A display element in which very little or no chiral component mixed inthe liquid crystal/polymer layer provides a polarization characteristicin all of the foregoing embodiments, and, therefore, can be employed inan electric field, control type polarization element.

In summary, the display element of this invention provides a reflectivetype display element of easy viewing and high brightness, compared toprior art displays which are dark and difficult to view. Further, thedisplay element of this invention also facilitates the combination ofactive elements, which are difficult to accomplish in prior artdisplays, thereby facilitating the production of large capacity,reflective type displays. Also, the display element of this inventionmakes possible reflective type, full color, large capacity displays forcomputer terminals and reflective type wall-mounted television displays,and also may be employed as an electric field, control type polarizationelement through the use of a simple configuration.

While the invention has been described in conjunction with severalspecific embodiments, it is evident to those skilled in the art thatmany further alternatives, modifications and variations will be apparentin light of the forgoing description. Thus, the invention describedherein is intended to embrace all such alternatives, modifications,applications and variations as may fall within the spirit and scope ofthe appended claims.

What is claimed is:
 1. A liquid crystal element having at least onesubstrate portion and an optical layer comprising liquid crystal andpolymer dispersed in said liquid crystal, said polymer comprisingpolymer grains being substantially aligned in the same alignmentdirection as said liquid crystal in absence of an applied electricfield, said polymer grains developed from the polymerization of at leastone polymer precursor containing at least one polymerizable portion andat least two aromatic rings with a coupling group bonded to saidaromatic rings, said at least one polymer precursor containing, as atleast one component, a polymer compound without an alkyl group spacerbetween said polymerizable portion and said aromatic rings.
 2. Theliquid crystal element of claim 1 wherein said coupling group comprisesan alkyl group or an alkoxy group bonded directly to said aromaticrings.
 3. The liquid crystal element of claim 1 wherein said couplinggroup comprises an alkyl group or an alkoxy group bonded indirectly tosaid aromatic rings.
 4. The liquid crystal element of claim 1 whereinsaid coupling group comprises at least one of a cyano group, a halogengroup or an aromatic ring bonded indirectly to said aromatic rings. 5.The liquid crystal element of claim 1 wherein said coupling groupcomprises at least one of a cyano group, a halogen group or an aromaticring bonded directly to said aromatic rings.
 6. The liquid crystalelement of claim 1 wherein said coupling group comprises an ester group.7. The liquid crystal element of claim 1 wherein said coupling groupcomprises a urethane group or an amide group.
 8. The liquid crystalelement of claim 1 wherein said coupling group comprises at least oneacetylene group.
 9. The liquid crystal element of any one of the claims1, 6, 7 and 8 wherein at least one of said aromatic rings may behydrogenated.
 10. The liquid crystal element of any one of claims 6through 8 or 1 through 5 wherein said polymer grains are ellipticalneedle-shaped grains and are linked in series.
 11. The liquid crystalelement of any one of claims 6 through 8 or 1 through 5 wherein saidpolymer precursors are selected from the group consisting of an esterderivative with methacrylic acid or acrylic acid, an amide derivativewith methacrylic acid or acrylic acid, and a compound containing anepoxy group.
 12. The liquid crystal element of any one of claims 6through 8 or 1 through 5 wherein said optical layer includes a dichroicdye.
 13. The liquid crystal element of any one of claims 6 through 8 or1 through 5 wherein said optical layer includes a chiral component. 14.A liquid crystal element having at least one substrate portion and anoptical layer comprising liquid crystal and polymer dispersed in saidliquid crystal, said polymer comprising polymer grains beingsubstantially aligned in the same alignment direction as said liquidcrystal in absence of an applied electric field, said polymer grainsdeveloped from the polymerization of at least one polymer precursorcontaining at least one polymerizable portion and at least two aromaticrings with a coupling group bonded to said aromatic rings, said at leastone polymer precursor containing, as at least one component, a polymercompound without an alkyl group spacer between said polymerizableportion and said aromatic rings and contains a halogen bonded to atleast one of said aromatic rings.
 15. The liquid crystal element ofclaim 14 wherein said halogen is fluorine.
 16. The liquid crystalelement of claim 14 wherein said polymer grains are ellipticalneedle-shaped grains and are linked in series.
 17. The liquid crystalelement of claim 14 wherein said polymer precursors are selected fromthe group consisting of an ester derivative with methacrylic acid oracrylic acid, an amide derivative with methacrylic acid or acrylic acid,and a compound containing an epoxy group.
 18. The liquid crystal elementof claim 14 wherein said optical layer includes a dichroic dye.
 19. Theliquid crystal element of claim 14 wherein said optical layer includes achiral component.
 20. The liquid crystal element of claim 15 whereinsaid polymer grains are elliptical needle-shaped grains and are linkedin series.
 21. The liquid crystal element of claim 15 wherein saidpolymer precursors are selected from the group consisting of an esterderivative with methacrylic acid or acrylic acid, an amide derivativewith methacrylic acid or acrylic acid, and a compound containing anepoxy group.
 22. The liquid crystal element of claim 15 wherein saidoptical layer includes a dichroic dye.
 23. The liquid crystal element ofclaim 15 wherein said optical layer includes a chiral component.
 24. Theliquid crystal element of claim 14 wherein said coupling group comprisesat least one group selected from the group consisting of an ester group,a urethane group, an amide group and an acetylene group.
 25. The liquidcrystal element of claim 14 wherein said polymer precursor is selectedfrom the group consisting of compounds having one of the followinggeneral formulae: ##STR47## wherein: G₁ is selected from the groupconsisting of acrylic acid, methacrylic acid, crotonic acid, fumaricacid, maleic acid, vinyl, and epoxy groups, optionally substituted witha halogen or an alkyl group, or is a compound having the formula:##STR48## wherein Y₁, Y₂, and Y₃ are independently selected fromhydrogen, fluorine, an alkyl group and a fluorinated alkyl group andwherein at least one of Y₁, Y₂, and Y₃ contains fluorine, and wherein Ris an ether group, an alkyl group, or an ester group with one or morephenyl groups;P₁, P₂, P₃ and P₄ are independently selected from groupscontaining an aromatic ring, optionally substituted with one or more ofhydrogen, a cyano group, a halogen, an alkyl group and an alkoxy group;A is selected from the group consisting of OCONH, NHCOO, NHCO and CONH;G₂ is independently selected from the group consisting of G₁ and H; Xand Y are substituents selected from the group consisting of CN, ahalogen, an aromatic ring, an alkyl group, and an alkoxy group; l and mare integers of 0 or greater; n is an integer of 1 or more; R₁ isselected from the group consisting of H, CH₃ and an alkyl group; B is anacetylene group; D is a group selected from the group consisting of anester group, an ether group, an amide group and an alkyl group; R₂ is analkyl group or an alkoxy group; Z is O or N; P₅ is an optically activegroup comprising an aromatic ring, optionally substituted with one ormore of hydrogen, a cyano group, a halogen, an alkyl group and an alkoxygroup; G₃ is an epoxy group R₃ is selected from the group consisting ofan alkyl group, an ester group, an amide group, and a urethane group;and E is selected from the group consisting of an ester group, aurethane group, an amide group, and an acetylene group.
 26. The liquidcrystal element of claim 25 wherein P₁, P₂, P₃ and P₄ are selected fromgroups having a phenyl, biphenyl, terphenyl, naphthalene and anthracenegroup.
 27. A liquid crystal element having at least one substrateportion and an optical layer comprising liquid crystal and polymerdispersed in said liquid crystal, said polymer comprising polymer grainsbeing substantially aligned in the same alignment direction as saidliquid crystal in absence of an applied electric field, said polymergrains developed from the polymerization of at lest one polymerprecursor containing at least one polymerizable portion and at least twoaromatic rings with a coupling group bonded to said aromatic rings, saidat least one polymer precursor containing, as at least one component, anoptically active polymer compound without an alkyl group spacer betweensaid polymerizable portion and said aromatic rings.
 28. The liquidcrystal element of claim 27 wherein said polymer grains are ellipticalneedle-shaped grains and are linked in series.
 29. The liquid crystalelement of claim 27 wherein said polymer precursors are selected fromthe group consisting of an ester derivative with methacrylic acid oracrylic acid, an amide derivative with methacrylic acid or acrylic acid,and a compound containing an epoxy group.
 30. The liquid crystal elementof claim 27 wherein said optical layer includes a dichroic dye.
 31. Theliquid crystal element of claim 27 wherein said optical layer includes achiral component.
 32. A liquid crystal element having at least onesubstrate portion and an optical layer comprising liquid crystal andpolymer mutually dispersed in one another, said substrate portionsubjected to an alignment treatment effective in the directionalalignment of said liquid crystal and said polymer, said polymercomprising polymer grains formed from at least one polymer precursorcomprising at least one polymerizable portion and at least one aromaticring, said polymer precursor undergoing polymerization throughexternally applied stimulus while aligned with said liquid crystal in apredetermined direction via said substrate portion treatment whereinsaid liquid crystal element is light transparent in absence of anelectric field and is light scattering in presence of an appliedelectric field, and wherein said at least one polymer precursor containsat least one component macromolecule precursor having two or morepolymerizable portions.
 33. The liquid crystal element of claim 32wherein said liquid crystal element comprises two substrate portions,said directional alignment of said liquid crystal and macromoleculegrains is controlled by alignment treatment subjected to surfaces ofboth of said substrate portions between which said liquid crystal andpolymer are sandwiched.
 34. The liquid crystal element of claim 33wherein a multi-color filter is formed on one of the substrates.
 35. Aliquid crystal element having at least one substrate portion and anoptical layer comprising liquid crystal and polymer mutually dispersedin one another, said substrate portion subjected to an alignmenttreatment effective in the directional alignment of said liquid crystaland said polymer, said polymer comprising polymer grains formed from atleast one polymer precursor comprising at least one polymerizableportion and at least one aromatic ring, said polymer precursorundergoing polymerization through externally applied stimulus whilealigned with said liquid crystal in a predetermined direction via saidsubstrate portion treatment wherein said liquid crystal element is lighttransparent in absence of an electric field and is light scattering inpresence of an applied electric field, and wherein said at least onepolymer precursor contains at least one component comprising an amidederivative of methacrylic acid or acrylic acid.
 36. The liquid crystalelement of claim 35 wherein said liquid crystal element comprises twosubstrate portions, said directional alignment of said liquid crystaland macromolecule grains is controlled by alignment treatment subjectedto surfaces of both of said substrate portions between which said liquidcrystal and polymer are sandwiched.
 37. The liquid crystal element ofclaim 36 wherein a multi-color filter is formed on one of thesubstrates.
 38. A liquid crystal element having at least one substrateportion and an optical layer comprising liquid crystal and polymermutually dispersed in one another, said substrate portion subjected toan alignment treatment effective in the directional alignment of saidliquid crystal and said polymer, said polymer comprising polymer grainsformed from at least one polymer precursor comprising at least onepolymerizable portion and at least one aromatic ring, said polymerprecursor undergoing polymerization through externally applied stimuluswhile aligned with said liquid crystal in a predetermined direction viasaid substrate portion treatment wherein said liquid crystal element islight transparent in absence of an electric field and is lightscattering in presence of an applied electric field, and wherein said atleast one polymer precursor contains at least one component comprising acompound having an epoxy group.
 39. The liquid crystal element of claim38 wherein said liquid crystal element comprises two substrate portions,said directional alignment of said liquid crystal and macromoleculegrains is controlled by alignment treatment subjected to surfaces ofboth of said substrate portions between which said liquid crystal andpolymer are sandwiched.
 40. The liquid crystal element of claim 39wherein a multi-color filter is formed on one of the substrates.
 41. Aliquid crystal element having at least one substrate portion and anoptical layer comprising liquid crystal and polymer mutually dispersedin one another, said substrate portion subjected to an alignmenttreatment effective in the directional alignment of said liquid crystaland said polymer, said polymer comprising polymer grains formed from atleast one polymer precursor comprising at least one polymerizableportion and at least one aromatic ring, said polymer precursorundergoing polymerization through externally applied stimulus whilealigned with said liquid crystal in a predetermined direction via saidsubstrate portion treatment wherein said liquid crystal element is lighttransparent in absence of an electric field and is light scattering inpresence of an applied electric field, and wherein said at least onepolymer precursor contains at least one component comprising a compoundhaving at least two aromatic rings and an ester group between saidaromatic rings.
 42. The liquid crystal element of claim 41 wherein saidliquid crystal element comprises two substrate portions, saiddirectional alignment of said liquid crystal and macromolecule grains iscontrolled by alignment treatment subjected to surfaces of both of saidsubstrate portions between which said liquid crystal and polymer aresandwiched.
 43. The liquid crystal element of claim 42 wherein amulti-color filter is formed on one of the substrates.
 44. A liquidcrystal element having at least one substrate portion and an opticallayer comprising liquid crystal and polymer mutually dispersed in oneanother, said substrate portion subjected to an alignment treatmenteffective in the directional alignment of said liquid crystal and saidpolymer, said polymer comprising polymer grains formed from at least onepolymer precursor comprising at least one polymerizable portion and atleast one aromatic ring, said polymer precursor undergoingpolymerization through externally applied stimulus while aligned withsaid liquid crystal in a predetermined direction via said substrateportion treatment wherein said liquid crystal element is lighttransparent in absence of an electric field and is light scattering inpresence of an applied electric field, and wherein said at least onepolymer precursor contains at least one component comprising a compoundhaving at least two aromatic rings and a urethane group or amide groupbetween these aromatic rings.
 45. The liquid crystal element of claim 44wherein said liquid crystal element comprises two substrate portions,said directional alignment of said liquid crystal and macromoleculegrains is controlled by alignment treatment subjected to surfaces ofboth of said substrate portions between which said liquid crystal andpolymer are sandwiched.
 46. The liquid crystal element of claim 45wherein a multi-color filter is formed on one of the substrates.
 47. Aliquid crystal element having at least one substrate portion and anoptical layer comprising liquid crystal and polymer mutually dispersedin one another, said substrate portion subjected to an alignmenttreatment effective in the directional alignment of said liquid crystaland said polymer, said polymer comprising polymer grains formed from atleast one polymer precursor comprising at least one polymerizableportion and at least one aromatic ring, said polymer precursorundergoing polymerization through externally applied stimulus whilealigned with said liquid crystal in a predetermined direction via saidsubstrate portion treatment wherein said liquid crystal element is lighttransparent in absence of an electric field and is light scattering inpresence of an applied electric field, and wherein said at least onepolymer precursor contains at least one component comprising a compoundhaving at least two aromatic rings and at least an acetylene groupbetween these aromatic rings.
 48. The liquid crystal element of claim 47wherein said liquid crystal element comprises two substrate portions,said directional alignment of said liquid crystal and macromoleculegrains is controlled by alignment treatment subjected to surfaces ofboth of said substrate portions between which said liquid crystal andpolymer are sandwiched.
 49. The liquid crystal element of claim 48wherein a multi-color filter is formed on one of the substrates.
 50. Aliquid crystal element having at least one substrate portion and anoptical layer comprising liquid crystal and polymer mutually dispersedin one another, said substrate portion subjected to an alignmenttreatment effective in the directional alignment of said liquid crystaland said polymer, said polymer comprising polymer grains formed from atleast one polymer precursor comprising at least one polymerizableportion and at least one aromatic ring, said polymer precursorundergoing polymerization through externally applied stimulus whilealigned with said liquid crystal in a predetermined direction via saidsubstrate portion treatment wherein said liquid crystal element is lighttransparent in absence of an electric field and is light scattering inpresence of an applied electric field, and wherein said at least onepolymer precursor contains at least one component comprising a polymercompound including a halogen atom.
 51. The liquid crystal element ofclaim 50 wherein said liquid crystal element comprises two substrateportions, said directional alignment of said liquid crystal andmacromolecule grains is controlled by alignment treatment subjected tosurfaces of both of said substrate portions between which said liquidcrystal and polymer are sandwiched.
 52. The liquid crystal element ofclaim 51 wherein a multi-color filter is formed on one of thesubstrates.
 53. A liquid crystal element having at least one substrateportion and an optical layer comprising liquid crystal and polymermutually dispersed in one another, said substrate portion subjected toan alignment treatment effective in the directional alignment of saidliquid crystal and said polymer, said polymer comprising polymer grainsformed from at least one polymer precursor comprising at least onepolymerizable portion and at least one aromatic ring, said polymerprecursor undergoing polymerization through externally applied stimuluswhile aligned with said liquid crystal in a predetermined direction viasaid substrate portion treatment wherein said liquid crystal element islight transparent in absence of an electric field and is lightscattering in presence of an applied electric field, and wherein said atleast one polymer precursor contains at least one component comprisingan optically active polymer compound.
 54. The liquid crystal element ofclaim 53 wherein said liquid crystal element comprises two substrateportions, said directional alignment of said liquid crystal andmacromolecule grains is controlled by alignment treatment subjected tosurfaces of both of said substrate portions between which said liquidcrystal and polymer are sandwiched.
 55. The liquid crystal element ofclaim 54 wherein a multi-color filter is formed on one of thesubstrates.